Domain redistribution within ergosterol-containing model membranes in the presence of the antimicrobial compound fengycin

Publication date: Available online 10 January 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Elisabeth Mantil, Trinda Crippin, Tyler J. AvisAbstractThe cyclic lipopeptide fengycin, produced by Bacillus subtilis, exhibits its antimicrobial capabilities by altering the integrity of the cell membrane of plant pathogens. Previous work has correlated fengycin activity with membrane characteristics, such as sterol content. This work focused on the influence of fengycin on supported lipid bilayers containing varying levels of ergosterol. Total internal reflection fluorescence (TIRF) microscopy was used to visualize and distinguish ordered (Lβ/Lo) and disordered (Lα/Ld) domains in the model membranes following exposure to low (50 μg) and high (500 μg) fengycin doses. Application of an initial low dose of fengycin to 0% and 3% ergosterol-containing bilayers resulted in redistribution of Lα/Lβ and Lo/Ld domains, respectively, which the bilayers compensated and corrected for over time. These membranes were unable to tolerate a second 50 μg dose or a single high fengycin dose. The 6% ergosterol bilayers were able to tolerate sequential low doses of fengycin. Exposure of these bilayers to the high fengycin dose caused a decrease in the number of Lo domains, albeit less than that seen in the 0% and 3% ergosterol bilayers. Bilayers containing 12% ergosterol, exhibited the least amount of change after fengycin exposure. These were the only bilayer to ex...

Source: Biochimica et Biophysica Acta (BBA) Biomembranes - January 11, 2019 Category: Biochemistry Source Type: research